I am rattle can painting many parts on my bike. I started with the lower forks this week and I have a slight problem. I sanded down my forks with 80 grit sandpaper, primed it, and then painted it with an additional 4 coats. After doing that the paint job looked great, but the paint chips away really easy. Is there a way to fix this problem? I should also mention that I am going with a matte black paint so I can really use a clear coat. If you have any suggestions please let me know how to fix this, I have a HOG meeting to go to on Sunday.

Thanks,

Phil

 

Sounds like it wasn't preped right.

GT

 

What needed to be prepped different? Was I supposed to sand after the primer, or did I need to use a higher grit paper to end with?

 

What did you clean it with before painting? Did you sand it to create texture? Or to remove th factory clear coat? Bare alum requires a special primer. Although I have gotten away with a simple selft etching primer before.

 

When it flakes does it flake to the metal or just the topcoat?

GT

 

Bobcowan - I used paint thinner to clean it initially. Then I sanded it down to nothing but bare aluminum, which created the texture.

SprigerGT - It is flaking just to the primer.

I live in England and it's not the warmest weather here right now. I am painting the tube in a bay that is somewhat heated, maybe about 60 degrees. Do you think that has anything to do with it?

 

Once you shot the primer and it dried ,did you sand the primer? I always hit the primer with sandpaper to knock down any runs and to prepare for my color coat.

 

No I didn't sand it after the prime. Should I use a high grit sandpaper?

 

I've done some auto painting in the past, so here's my two cents. After your first sanding (80 grit) and cleaning use a tack cloth to remove any particles from the surface. You should sand (200 grit) you primer coat and use the tack cloth again. Apply topcoat/s and if you are using a matte finish with clearcoat to follow, one final wet sanding with 1000 grit.

Question
Rattle can paint has a shelf life, how old is the paint?
60 degrees F shouldn't be too cool for painting, what's the humidity? Paint will pick up excess moisture during application.

 

are you using primer made for that type of paint? if you spray different kinds of paint over another it will spider, and crack it up. like a lauqer over a urathene base